Hydraulic pressure device



1 Patented June 29, i937 UNITED STATE nymummc masons nnvlcn Hermann KurtWdllc, Beflin. Germany Application June 12,

In Germany nus-sum as. June 1:, 19:4

120mm:- (eta-54.6)

This inve ntion' relates to a. hydraulic pressure device, moreparticularly a brake, wherein a threaded spindle adapted to be operatedby hand drives a piston in a pressm'e cylinder and places theC-liquidcolumn, whichis in frontof the piston,

under pressure which is transmitted ina known mannerthrough a pressurepipe. In such pressure devices, it is necessary to maintain the pressureonce produced for a long pe od. Owing to special circumstances, forinstance, owing to the contraction of the fluid due to thereduction ofthe outer temperature or to leakage in the pressure system, lossesofpressure may occur which arenot perceptible externally.

1 The present invention has for its object to I tionoi pressure in thepressure device is rendered easily visible to the operator so that thedefect can be immediately remedied. The present in- 20 ventinn ischaracterized by a an indicating device, which consists of a rodconnected to the piston in the pressure cylinder,

the said piston being actuated by a pressure spring. Therod passesthrough the hollow driv- .ing spindle and ton externally. The drivingspindle is advantagcously arranged in such a manner that it is easilyreached and visible from the driver's seat.

, The device according to the invention is illustrated in aconstructional example in the accomp'anying drawing, in which: n

- Fig. 1 shows an automobile in elevation with.

the new pressuredevice actingas hand brake;

2 illustrates the essential parts of the hydraulic pressure devicediagrammatically, and Fig: 3' shows the pressure cylinder with the piston which is driven by hand through a threaded spindle in partlongitudinal section.

' In the drawing I is a pressure cylinder, which is secured by means ofthe flange 2 and screws 3 on to the d -board 4 of, the automobile 5.

6 is a connection for the brake pipe I from the pressure cylinder Ileading to the wheel braking H cylinders 8 0! the vehicle. The pipe 1opens into the pressure space The two oppositely moving pistons III ofeach brake cylinder co-act with the'brake blocks ll which are drawntogether by tension springs l2 are not forced apart by the pressureprevin the space 8 when the brakes are appliedand pres sagainst the brakedrum- II of the vehicle wheels. p i In. "the-pressi1re cylinder I thepiston ll is guided. 5 i5 preferabl aslong as they of rubber.

provide a simple arrangement whereby areducthe arrangement of indicatesthe position of the pis- 9o! thewheefbrake cylinder.

the iront end oi which carries 'a packing {the pressure cylinder endlay-the inserted cover side carries a bearing is closed atthe real: It,which on the o bush-i1. 'lhecover lialsolimitstherearward motion of thepiston Ill. This is driven by a hollowspindie I: having an externalthread I! at 5 the end turther from the piston, which-screws into athread inthe cover Ii of the cylinder. 0n the other free end the hollowspindle 18 has a handknob 2| ilrinly secured thereto, whichisan'angedsoasto beeasilyreached from the 10 driver's seat (see Fig. 1).Between thepiston II and the threaded spindle II, I! a springll isinterposed. Thisspringrests at one endon the backer the piston ",andatthe other end against the spring member 22, which in its tmnTestsagainst the driving spindle II. The interposed spring il-which, as shownin Fig. .3 is enclosed onallsidesisweakerthanthereturnspring l2iorthebrakeblocksll.

Ontherearslde oithepistonthereissecured g0inthecentreinasuitablemannerathinrod 23 which passes axially through thehollow spindie I! and the spindle 2|, and projects a little the'latter,-so as who visible.

parts of the pressure device 25 l v axiallyone behindanother sothat-they can 7 pressure cylinder as aunit, and movedagain. t Whenthehandle I. isturnedthe spindle ll, il -is screwed into the cover lfi. IIthe spindle is thedirectionoftheplston ilit presses against the springplaten. 'Ihepressureistransmittedthroughthespring 2i tothe piston whichis moved forward a corresponding 5 distanceinthe i. withthepistonfor-wardinthe cylinder I thefluidpressureinthe 'systemisinc ,and,ifn,canbeincreased to such an extent that the brake blocks are forcedagaihst the Th e driving spindle [8 cannot rotate-unintentlonally andwhen the operating handle 2| isadjusteithepressurecorrespondingtdtheactual position ofthe piston in thecylinder is maintalliedbrakedrum ll. Inthis 4d 20 has an exactindication of When there is adrop in fluid pressure due to externaltemperature influence or leakage, the pressure'spring 2|, which issubjected to great tension, moves the piston I 4 forward so that theloss of pressure is immediately compensated. The fluid pressure oncefixedis thereby, always maintained provided that the liquid has notcompletely escaped. a

By means of a rod 23 which-is connected with 10 the piston .H andprojects beyond the handle 2| s0 asto be visible, the actual state ofthe brake isindicatedto the driver. The rod 23 takes part in themovements of the piston I I. If, for example, there is a loss of fluidresulting in the 15 piston .being moved forwards by the spring II thiswill be recognized by rod 23 projecting out of the the'iree end oi thehandle 20 being retracted. If this end is no longer'visible, having beendrawn right back into the handle, the driver the actual state of thebrake. If necessary thecap 24 must be screwed oii and'more liquid filledin.

I What I claim is:-

1. A hydraulic hand brake for automobiles or the like, comprising afluid cylinder, 9. piston in said cylinder movable therein for actuatingthe brake, a spindle for driving said piston, spring means interposedbetween the piston and said spindle and acting on said piston forautomatically regulating the pressure in said cylindenand a rod securedat one end to said piston and extending axially through the spindle forindicating the position of the piston in saidcylinder.

2. A hydraulic hand brakei'or automobiles or the like, comprising afluid cylinder, a piston in said cylinder movable therein for actuatingthe brake, a spindle extending into said cylinder for actuating saidpiston, spring means in said cylinder interposed between the piston andsaid spindle and acting on said piston for automatically'regulating thepressure in said cylinder, and a rod having one end secured to thepiston and extending axially through the spindle outside the cylinderfor indicating the position of the piston within said cylinder.

HERMANN KURT WEIHE.

